In this thriving world of mobile communications, the difficulty of communication is no longer contacting someone (the receiver), but rather contacting them in a socially appropriate manner. Ideally, senders should have some understanding of a receiver's availability in order to make contact at the right time, in the right contexts, and with the optimal communication medium. This paper describes our ongoing research on the Connector, an adaptive and contextaware service designed to facilitate efficient and appropriate communication. We describe a set of empirical studies whose results converge upon the important subject of people's availability in mobile contexts.